In the earth working field it is quite often necessary to loosen the surface of the ground before earth removal takes place. If the terrain has not been broken before, it may be appropriate to break the earth to depths of 3 to 4 ft. or more. It has been found that the force required to pull the ripper shank and the ripper tooth through the earth is generally proportional to the square of the depth of penetration of the earth. Accordingly, to increase the ripping depth from 2 ft. to 4 ft. requires approximately four times the force for twice the depth. Of course, it is possible to work the earth twice, that is, the first pass ripping to 2 ft. while the second pass ripping from 2 ft. to 4 ft. Obvious economic considerations dictate the preference for the single pass approach to effect the 4 ft. depth out.
Mounting two ripper teeth in tandem with the trailing tooth being disposed at a greater depth than the leading tooth accomplishes the same work as a single tooth mounted at the greater depth. Furthermore, such tandem arrangement requires only approximately one-half the force to effect the 4 ft. depth cut, for example, in comparison to a single tooth arrangement maintained at the 4 ft. depth.
The broad concept of fixedly mounting two ripper teeth in tandem relationship on a vehicle may not prove effective since there would be a tendency for them to clog with earth. Thus, the cutting efficiency of the second tooth may be seriously impaired. This invention is primarily directed to the provision of the tandem ripper assembly which exhibits a high degree of cutting efficiency while yet insuring that they will not become unduly clogged during operation.
Tandem ripper teeth mounted on a rigid assembly would result in the rear-most tooth being the longest, entering the ground first as the assembly is lowered from a transport condition to an operative condition. Rather than penetrating the earth, the rear-most tooth could have a tendency to raise the rear end of the vehicle due to the relatively long moment arm extending from the center of gravity of the towing vehicle to the point of contact of the tip with the ground. On the other hand, the conventional single tooth does not have this disadvantage because it is more closely coupled to the vehicle.